Nowadays, many electronic devices such as chipsets and RAMs would generate large amounts of heat during the operation. The heat must be removed efficiently. Otherwise, malfunction or damage may result. Due to the increasingly requirements in heat dissipation, various kinds of heat sink assemblies are proposed so as to dissipate the heat generated by the electronic devices more effectively.
Please refer to FIG. 1, which is an exploded perspective view of a conventional heat sink assembly 1 having a heat sink 11 and a retaining device 12, which is employed to mount the heat sink 11 on a first top 210 of a chipset assembly 2 (a heat source) so as to dissipate the heat generated by the heat source. The chipset assembly 2 further includes a chipset 21 having the first top 210, a substrate 22 and a PC board 23. The heat sink 11 further includes a plurality of fins 111 and a base 112 having a top surface 1121 and a base plate 1122. The retaining device 12 further includes a frame 121 having a second top 1210, four side portions 1211 and a hole 1212 with a size smaller than that of the base 112, two retaining plates 122 each with a barb 1221 mounting the heat sink 11 on the first top 210 of the chipset assembly 2, four elastic rods 123 extending inwards the hole from the second top 1210 of the frame 121 and each with a end portion 1231 bending towards the hole 1212 and pressing the heat sink 11, two positioning columns 124 extending downwards from the frame 121 and positioning the heat sink 11.
FIG. 2 is a schematic diagram showing that the conventional heat sink assembly 1 is mounted on the first top 210 of the chipset assembly 2. FIGS. 3(a) and 3(b) are a transverse cross sectional view of the conventional heat sink assembly 1 and the chipset assembly 2 of FIG. 2 and a longitudinal cross sectional view of the conventional heat sink assembly 1 and the chipset assembly 2 of FIG. 2 respectively. Referring to FIGS. 3(a) and 3(b), notice that the frame 121 would cover an outer portion of the base 112 such that no fin could be formed on the outer portion of the top surface 1121 of the base 112, which is covered by the frame 121 firstly. Thus, relatively the heat dissipation effectiveness of the heat sink assembly 1 would be lower since the heat sink 11 has less number of fins 111 secondly. And the airflow flows through the plurality of gaps 1111 formed therebetween the plurality of fins 111 would be blocked by the frame 121, which will dramatically damp the heat dissipation effectiveness of the heat sink assembly 1 especially when the height of the plurality of fins is relatively lower as is the case of FIG. 2 thirdly. These are the main drawbacks of the above-mentioned conventional heat sink assembly 1.
Keeping the drawbacks of the prior art in mind, and employing experiments and research full-heartily and persistently, the applicant finally conceived a heat sink assembly having a retaining device with relatively better heat dissipation effectiveness.